Nitroxide-Mediated Radical Copolymerization of Methyl Methacrylate Controlled with a Minimal Amount of 9-(4-Vinylbenzyl)-9H-Carbazole

The controlled nitroxide-mediated homopolymerization of 9-(4-vinylbenzyl)-9H-carbazole (VBK) and the copolymerization of methyl methacrylate (MMA) with varying amounts of VBK were accomplished by using 10 mol % {tert-butyl[1-(diethoxyphosphoryl)-2,2-dimethylpropyl]amino} nitroxide relative to 2-({tert-butyl[1-(diethoxyphosphoryl)-2,2-dimethylpropyl]aminoloxy)-2-methylpropionic acid (BlocBuilder (TM)) in dimethylformamide at temperatures from 80 to 125 degrees C. As little as 1 mol % of VBK in the feed was required to obtain a controlled copolymerization of an MMA/VBK mixture, resulting in a linear increase in molecular weight versus conversion with a narrow molecular weight distribution ((M) over bar (w)/(M) over bar (n) approximate to 1.3). Preferential incorporation of VBK into the copolymer was indicated by the MMA/VBK reactivity ratios determined: r(vBK) = 2.7 +/- 1.5 and r(MMA) = 0.24 +/- 0.14. The copolymers were found significantly living by performing subsequent chain extensions with a fresh batch of VBK and by 31P NMR spectroscopy analysis. VBK was found to be an effective controlling comonomer for NMP of MMA, and such low levels of VBK comonomer ensured transparency in the final copolymer. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 1033-1045, 2011